Electron tube and the like



March 25, 1941. s, m, QNEILL ELECTROH TUBE AND THE LIKE Filed Aug. 3', 1940 2 uests-Sheet 1 INVENTOR.

BY A TTOR E 7 March 25, 1941. s. D. ONElL-L.

ELECTRON TUBE AND TH LIKE 2 Sheets-Sheet 2 INVENTOR.

Filed Aug. 3, 1940 Patented Mar. 25, 1941 UNITED, STATES PATENT OFFICE ELECTRON TUBE AND THE LIKE Application August 3,

11 Claims.

This invention relates to electric discharge devices and in particular to radio tubes and similar articles of manufacture.

One of the standard methods of making radio tubes consists in mounting the electrodes of the tube mount on a stem or header through which all or most of the. electrode leads are sealed, sealing the stem or header to the envelope or bulb, exhausting the tube, and sealing it off.

The main support of the mount in the tube is from the stem to which it is mechanically attached in one of several ways well-known in the art. If the mount is supported in this way at one end of the tube only, say at the bottom, the top of the mount may, by external mechanical shock, be made to move slightly in any direction perpendicular to the axis of the tube. This may eventually lead to deformation or weakening of the mount or of its supporting structure, which in turn may result in changes of tube characteristics, noise during operation, or erratic performance of the tube, as well as in increased spoilage.

In order to obtain the mechanical strength necessary for more stable tube characteristics, less noise, and lower spoilage, a number of methods have previously been developed which supplement the one-ended support of the mount on the stem by a member which restrains the lateral motion of the upper end of the mount with respect to the envelope.

The invention provides a resilient support which prevents the undesirable movements left unrestricted by previous auxiliary top supports. It provides on the mount itself a bulb carrier or support which eliminates the need for a separate carrier on the sealing machine, because the mount is self-centering in the bulb and establishes the spacing in the axial direction as well as in the transverse direction. In addition, it provides an improved and simplified method of assembling to the upper end of the mount a top support which is of wire clip type. Furthermore, the invention overcomes a major difficulty which presents itself in the sealing-in of tubes using the older types of mount supports, in that it avoids the necessity for special care in placing the bulb over the mount to prevent damage to the support or to the mount itself.

Accordingly, it is an object of the invention to provide a top support for a radio tube mount which insures the desirable resilient support of the top of the mount in the envelope, which support is effective in substantially all directions.

Another object of the invention is to simplify 1940, Serial No. 359,313

the assembling of the top supports on the tube mount.

A feature of the invention refers to the shape of the slots provided in the top mount spacer, and also to the shape of wire clip which insures an easy insertion and a positive interlocking of the clip with the said spacer.

A further object of the invention is to provide automatic locating of the tube mount in the envelope during the sealing-in process, which will permit the mount itself to carry or support the bulb during sealing, making separate bulb carriers on the exhaust machine unnecessary. One feature of the invention consists in the automatic spacing between the top of the mount and the top of the envelope during sealing in. Another feature consists in the automatic centering of the mount in the envelope when the bulb is dropped over the mount prior to sealing.

Another object of the invention refers to the O shape and the forming of a wire clip which can be manufactured by a bending operation in a single plane.

A still further object of the invention is to make easier the sliding of the bulb over the mount and the support, to adapt the structure for high speed handling at an automatic sealing machine.

In the attached drawings:

Fig. 1 shows the Wire clip support according to the invention.

Fig. 2 shows a preferred form of top spacer member which carries the clip of Fig. 1.

Fig. 3 shows a modification of the top spacer of Fig. 2.

Fig. 4 is a sectional view of Fig. 3 along the line 44 thereof.

Fig. 5 shows how the clip is temporarily deformed during assembly with the spacer of Fig. 3.

Fig. 6 is a sectional View of the spacer of Fig. 2 showing the wire clip of Fig. 1 in place and in its normal or unflexed position.

Fig. 7 shows how the wire clip is temporarily deformed in assembling it into the spacer member of Figs. 2 and 6.

Fig. 8 is an exploded or assembly view of a radio tube mount and cooperating glass bulb or envelope according to the invention.

Fig. 9 is a top-plan view of the top spacer and wire clips before insertion. of the mount into the bulb of Fig. 8.

Fig. 1D is a side view of the top portion of the assembled mount and bulb.

Fig. 11 is another view of the top portion of wire or flat spring metal strip and comprises two downwardly depending free ends 2, 3, joined to the upper arched middle section 4 by reentrant bends 5. Preferably, although not necessarily, the wire is bent so that all portions thereof normally lie in substantially a single plane. The transverse spacing between the free ends 2 and 3 may be slightly greater than the internal diameter of the bulb wherein the clip is to be used so that engagement with the bulb walls provides a resilient engagement between the said ends and the bulb wall. The spacing between the bights of the reentrant bends 5 is slightly greater than the distance between the ends 6 of the retaining slots in the insulator spacer member I. A typical and preferred form of insulator spacer is shown in Fig. 2, this spacer being of any suitable insulating material such as mica, ceramic or the like, and being provided with a central row of perforations 8 to receive, in a manner well-known in the art, the ends of the various electrodes constituting the electrode assembly of the radio tube mount. Opposite edges of the spacer I are provided with a pair of L-shaped slots 9 to receive and anchor the corresponding clips such as those of Fig. 1. The clip may be assembled into spacer by pressing the free ends together, until the spacing between the point 5 equals the spacing between the entrance portion of slots 9 as indicated in Fig. 7, and, sliding the clip into its final position as indicated in Fig. 6. A better method of assembly in which the clip undergoes less deformation, consists of the steps, first to insert one-half of the clip so that the bend 5 rests in its final position in slot 9, then compressing the clip so that the other bend 5 can be slipped into the other slot 9. Upon release, the clip springs out to its final position, the bends 5 being at the extreme ends of slots 9.

Instead of using open-ended slots in the spacer 1, the spacer may be provided with closed slots, a typical spacer of this type being shown in planview in Fig. 3 and in cross-sectional view in Fig. 4. In order to assemble the wire clip into such a spacer the free ends 2, 3, are pressed together until they are close enough so that they may be inserted through the corresponding slots H in the spacer [2. Thus the clip is assembled into the spacer l2 substantially transverse to the plane of the spacer. When the ends 2 and 3 are released, the shoulder portions l0 will spring apart and engage the outer ends of the slots ll, thus holding the clip assembled in the spacer with substantially no freedom of movement except a limited rotation about the axis l0, In, (Fig. 1) for the purpose described hereinbelow. The spacer embodiment of Fig. 2 is preferred in that it enables the clips to be assembled more readily into the spacer and requires less deformation of the clip ends during assembly.

Fig. 9 shows the normal relation between the clips and the spacer after assembly from which it will be seen that the plane of each clip is substantially perpendicular to the plane of the spacer.

In Fig. 8, there is shown a typical radio tube mount consisting of the reentrant stem or press 13 into which are sealed the various lead-in and support wires for the electrode assembly indicated generally by the numeral [4. In the case of two-element tubes, this electrode assembly may consist of a cathode and an anode but it will be obvious that the electrode assembly may include any number of electrodes. The electrodes are spaced apart at their ends by a lower mica disc l5 and by the upper mica disc 1, it being understood that both discs are provided with appropriate aligned perforations 8 (Fig. 2) to receive the side rods or end portions of the various electrodes. The said spacer discs may be fastened to a pair of metal uprights I6, ll, by metal eyelets, tabs or the like, the said uprights being sealed into press l3. As shown in the exploded View of Fig. 8, the top spacer I may be considerably smaller in its maximum dimension than the inside diameter of the bulb 18, thus permitting rapid handling at the sealing machine.

As the bulb I8 is slipped over the mount, it encounters no resistance until it extends down past the top mica I and until the cylindrical portion of the bulb engages the free ends 2, 3, of the wire clips I. Prior to this engagement the clips hang as shown in Fig. 9 thus assuring free entry of the top of the mount into the bulb, and preferably, although not necessarily, the lower end or collet IQ of the bulb is flared slightly outwardly so as to facilitate the initial insertion of the bulb over the mount. As the bulb is moved further down, the cylindrical portion of the bulb engages the free ends of the clips which are thereby pressed towards each other, but being smoothly curved, these ends slide on the inner wall of the bulb out of their original planes and toward a parallel plane through the axis of the bulb, because the ends of each clip naturally tend to move in the direction permitting their greatest separation. As the ends 2, 3, move in this direction, each clip rotates on its l0ll axis (see Fig. 1) and the arched portions 4 move outwardly toward the bulb wall. The relation between the free ends of the clip and the arched ends 4 with respect to the cylindrical portion of the bulb I8 is shown more clearly in Figs, 10, 11 and 12. The angle through which each clip turns on its axis lfll0 when engaged by the bulb l8,

depends of course upon the relative diameter of the bulb and the dimensions of the clips and in any event this angle will be stabilized or established automatically where the stress on the clip is at a minimum. It will be seen that the spacing of the wire clips in the spacer is such that while the mount is in the process of being assembled into the cylindrical portion of the bulb, the arched portions 4 of the clips do not touch the bulb top wall 20. However, when the mount reaches its final position within the bulb I8, these portions 4 of the clips contact the top or arched portion 2|] of the bulb and by the joint action of these parts the mount and bulb are automatically centered in the proper axial relation. The engagement of the free ends 2, 3, with the cylindrical portion of the bulb, and the engagement of the arched portions 4 with the curved top portion of the bulb, set up symmetrical forces which center the mount automatically in the bulb during sealing and prevent lateral motion of the upper end of the mount in the bulb after the sealing has been completed. Furthermore, the portions 4 space the mount axially in the bulb. The combination of these two features makes the assembly ideal for supporting the bulb on the mount during sealing. This avoids the necessity of employing special bulb holding or retaining means on the sealing machine which are ordinarily provided to insure that the bulb is in the proper Vertical and axial relation with respect to the mount. Although in the foregoing description, mention has been made of a particular kind of bulb l8 which is mainly cylindrical in shape, this is done merely for purposes of explanation. It will be understood of course that the invention is applicable to other types and shapes of bulbs as are well-known in the radio tube industry. For example, the bulb l8 may be of the wellknown dome type or ST type in which event the clip arrangement cooperates with the cylindrical dome-shaped portion of the bulb in exactly the same manner as that described above. The foregoing arrangement in addition to providing a novel form of top support for the tube mount, reduces the cost of manufacture since it increases the assembly speed and prevents motion of the top of the mount in substantially all directions.

Various changes and modifications may be made in the disclosed embodiments without departing from the spirit and scope of the invention. Thus while the drawings show two clips arranged opposite to each other in the mica I, it will be understood that more than two such spacers may be employed. Furthermore, while the arched portion 4 is shown as of one particular shape, other arched shapes may be employed.

What I claim is:

1. An electron tube comprising an electrode mount including an electrode assembly, an enclosing bulb, and means to support the upper end of said mount comprising a flexible metal member attached to the mount and having a portion extending into flexible engagement the side of said bulb and another portion extending into engagement with the end of said bulb.

2. An electron tube comprising an electrode mount including an electrode assembly, an enclosing bulb for said assembly, and means to support the upper end of said mount with respect to the vertical and horizontal axes of said bulb, the last-mentioned means including a flexible metal clip interlocked with the mount and capable of tilting movement with respect to the said longitudinal axis, said clip having a portion flexibly engaging the side of the bulb and another portion engaging the end of the bulb.

3. An electron tube according to claim 1 in which said clip is formed with a central portion terminating in two downwardly depending free ends, said free ends engaging the side of the bulb and the said central portion engaging the end of the bulb.

4. An electron tube according to claim 1 in which said clip is formed or spring metal having shoulders at the free end to engage the side of the bulb, and with two other shoulders for locking the clip to an insulator spacer member.

5. An electron tube according to claim 1 in which said mount is provided with a pair of said metal clips which are arranged to support the said bulb thereon during the sealing of the mount into the bulb.

6. An electron tube comprising a bulb containing a mount including an electrode assembly and at least one insulator spacer member fastened to one end of said assembly, a pair of slots in said spacer member, and a flexible metal mountsupporting member carried by said spacer memher, said supporting member having a pair of shoulders interlocked with the edges of said slots and with extensions flexibly engaging the side wall of the said bulb and another extension engaging the top wall of said bulb.

'7. An electron tube according to claim 6 in which the said flexible metal members are interlocked with said insulator member so as to be capable of limited individual tilting movement with respect to the vertical axis of the mount.

8. An electron tube according to claim 6 in which the said flexible metal members are inclined downwardly towards the vertical axis of the mount.

9. An electron tube according to claim 6 in which said slots in said insulator member are closed.

10. An electron tube according to claim 6 in which said slots are formed in the edges of said insulator spacer member.

11. An electron tube according to claim 6 in which said slots are substantially L-shaped.

GEORGE D. ONEILL. 

